Fluorescence sensing and magnetic properties of three coordination polymers based on 6-(3,5-dicarboxylphenyl)nicotinic acid and pyridine/imidazole linkers

Abstract

Three new coordination polymers (CPs), formulated as {[Ni(HDCPN)(4,4′-bpy)(CH₃CH₂OH)(H₂O)₂]·0.5CH₃CH₂OH}_n (1), {[Ni₃(DCPN)₂(4,4-bibp)₄(H₂O)₄]·2CH₃CH₂OH·5H₂O}_n (2), and {[Cu₃(DCPN)₂(1,3-bimb)₃]·6H₂O·2DMF}_n (3) (H₃DCPN = 6-(3,5-dicarboxylphenyl)nicotinic acid and 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl)benzene, 4,4′-bpy = 4,4′-bipyridine, 4,4′-bibp = 4,4′-bis(benzoimiazo-1-yl)biphenyl) were synthesized under hydrothermal conditions. These CPs were researched in depth by single-crystal X-ray diffraction analysis, elemental analysis (EA), IR spectroscopy, thermogravimetric analysis (TGA) and X-ray diffraction powder (PXRD) analysis. The structural analysis reveals that complex 1 exhibits a traditional 2-nodal (3,5)-{6³}{6⁹·8}-hms network, complex 2 shows a new 2D {6³}{6⁵·8}, and complex 3 exhibits a novel 3D (3,4)-c pillar-layered architecture with a point symbol of {6³}₂{6⁴.8.10}₃. Furthermore, magnetic studies show that complexes 1 and 2 exhibit antiferromagnetic properties. In addition, fluorescence measurements show that 3 can be applied as a probe for highly sensitive and selective detection of nitroaromatics and Fe³⁺ ions.